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Third SPL Collaboration Meeting. Working Group 1 WG1 Summary & Plan with Recommendations to the CB. Key Aims for WG1. Confirm baseline layout for Low/High B sections - Performance of the different layout options
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Third SPL Collaboration Meeting Working Group 1 WG1 Summary & Plan with Recommendations to the CB Third SPL Collaboration Meeting, CERN November 2009
Key Aimsfor WG1 • Confirm baseline layout for Low/High B sections • - Performance of the different layout options • Stability/repeatability attainable in presence of microphonics, Lorenz detuning, detuned cavities, reflections due to RF distribution component imperfections • - Difficulties with long waveguides (e.g. for RF Feedbacks)? • Power Margins needed – identify & quantify definitively – bad/good cavities • Klystron Modulator specs and design options – HPSPL needs, including space & integration ! • Power Coupler options – existing design & experience, overall review, requirements to get to high power – studies needed, prototyping requirements • Integration studies, get first version of Klystron Gallery layout / Integration • Investigate cost-cutting solutions in the RF Power and LLRF systems Third SPL Collaboration Meeting, CERN November 2009
Third SPL Collaboration Meeting - WG1 List of Presentations Modulators - Company Presentation SCANDINOVA KlasElmquist (SCANDINOVA SYSTEMS AB) Magnetron Power Sources Amos Dexter (Lancaster U.) Tuner design and performance Guillaume Devanz (CEA) Coupleurs XFEL-Spécifications Techniques et Stratégie Industrielle AboudFalou (LAL) Conditionnement HF des coupleurs TTF-3 et critères XFEL LucijaLukovac (LAL) CEA Saclay Coupler Tests Guillaume Devanz CEA) SPL coupler options and integration requirements Eric Montesinos (CERN) Development paths for High average RF Power Couplers Eric Montesinos (CERN) Lorentz force detuning measurements on the CEA cavity Daniel Valuch (CERN) RF simulations W. Hofle, Mathias Hernandez (CERN) + Specialist Input – R. Rimmer, (JLAB) R. Pasquinelli (Fermilab)
WG1 Presentations Modulators - SCANDINOVA – K. Elmquist
Klystron Modulator Specs One modulator per klystron, driving 2 cavities LP-SPL (500 kW on cavity) flat top: 1.8 ms rep-rate: 2 Hz voltage: 110 kV droop: 5% power: 3.2-3.4 MW (500 kW per cavity) + margin for splitting and LLRF + 50% klystron efficiency) HP-SPL (1 MW on cavity) flat top: <2.1 ms rep-rate: 50 Hz voltage: 110 kV droop: 5% power: 6.4-6.8 MW (1 MW per cavity + margin for splitting and LLRF + 50% klystron efficiency Third SPL Collaboration Meeting, CERN November 2009
Basic schematic of the Scandinova modulator N = number of primary circuits R = Klystron Resistance NT= Transformer ratio (Has to be compensated for with N) C Transformer Klystron PS Switch C PS Switch
Klystron C Transformer Tuning PS Switch Rt = Tuning resistance Lt= Tuning inductance Tuning
A magnetron solution for SPL? Amos Dexter, ImranTahir, Bob Rimmer and Richard Carter
Magnetrons for Accelerators Single magnetrons 2.856 GHz, 5 MW, 3ms pulse, 200 Hz repetition are used to power linacs for medical and security applications. Multiple magnetrons have been considered for high energy normal conducting linacs but the injection power needed for an unstabilised magnetron made it uncompetitive with a Klystron. Overett, T.; Bowles, E.; Remsen, D. B.; Smith, R. E., III; Thomas, G. E. “ Phase Locked Magnetrons as Accelerator RF Sources” PAC 1987 Benford J., Sze H., Woo W., Smith R., and Harteneck B., “Phase locking of relativistic magnetrons” Phys. Rev.Lett., vol. 62, no. 4, pp. 969, 1989. Treado T. A., Hansen T. A., and Jenkins D.J. “Power-combining and injection locking magnetrons for accelerator applications,” Proc IEEE Particle Accelerator Conf., San Francisco, CA 1991. Chen, S. C.; Bekefi, G.; Temkin, R. J. “ Injection Locking of a Long-Pulse Relativistic Magnetron” PAC 1991 Treado, T. A.; Brown, P. D.; Hansen, T. A.; Aiguier, D. J. “ Phase locking of two long-pulse, high-power magnetrons” , IEEE Trans. Plasma Science, vol 22, p616-625, 1994 Treado, Todd A.; Brown, Paul D., Aiguier, Darrell “New experimental results at long pulse and high repetition rate, from Varian's phase-locked magnetron array program” Proceedings Intense Microwave Pulses, SPIE vol. 1872, July 1993 Courtesy of e2v
The Reflection Amplifier Cavity Load Magnetron Circulator Injection Source • Linacs require accurate phase control • Phase control requires an amplifier • Magnetrons can be operated as reflection amplifiers Compared to Klystrons, in general Magnetrons - are smaller - more efficient - can use permanent magnets (at 704 MHz) - utilise lower d.c. voltage but higher current - are easier to manufacture Consequently they are much cheaper topurchase and operate J. Kline “The magnetron as a negative-resistance amplifier,” IRE Transactions on Electron Devices, vol. ED-8, Nov 1961 H.L. Thal and R.G. Lock, “Locking of magnetrons by an injected r.f. signal”, IEEE Trans. MTT, vol. 13, 1965
Adler’s Equation for Injection Locking J.C. Slater “The Phasing of Magnetrons” MIT Technical Report 35, 1947 Shien Chi Chen “Growth and frequency Pushing effects in Relativistic Magnetron Phase – Locking”, IEEE Trans. on Plasma Science Vol. 18 No 3. June 1990. The basic circuit model for the phased locked magnetron is the same as for a cavity Injection Load impedance includes pulling effects. Negative impedance to represent magnetron spokes excitation of the anode. Includes static pushing effects. C -ZS Zw L R To get Adler’s equation set to give
Layout using one magnetron per cavity Permits fast phase control but only slow, full range amplitude control A substantial development program would be required for a 704 MHz, 880 kW long pulse magnetron Cavity Standard Modulator 880 kW Magnetron Load 4 Port Circulator Pulse to pulse amplitude can be varied Slow tuner 60 kW IOT LLRF ~ -13 dB to -17 dB needed for locking i.e. between 18 kW and 44kW hence between 42 kW and 16 kW available for fast amplitude control Could fill cavity with IOT then pulse magnetron when beam arrives
Layout using two magnetrons per cavity 440 kW Magnetron 440 kW Magnetron 440 W 440 W Permits fast full range phase and amplitude control Phasor diagram output of magnetron 1 output of magnetron 2 Cavity combiner / magic tee Advanced Modulator Advanced Modulator Load Fast magnetron tune by varying output current Fast magnetron tune by varying output current ~ -30 dB needed for locking LLRF 440 kW Magnetron design is less demanding than 880 kW design reducing cost per kW, and increasing lifetime and reliability.
Magnetron Size air cooling for cathode water cooling for anode dg Magnet dm hm If magnetron design is similar to industrial design with similar tolerances and can be made on same production line then cost may not be much more air cooling input for dome
Experiments at Lancaster Double Balance Mixer Oscilloscope 2 Stub Tuner 2 Loop Coupler 3 Stub Tuner 1 Water Load Loop Coupler Circulator 1 10 Vane Magnetron Water Load 1W Amplifier Circulator 2 C3 Load Power supply ripple IQ Modulator (Amplitude & phase shifter) D/A Oscilloscope A/D D/A Magnetron phase no LLRF DSP LP Filter 8 kHz cut-off Digital Phase Detector 1.3GHz D/A ÷ M ÷ M pk-pk 26o High Voltage Transformer Magnetron phase with LLRF pk-pk 1.2o Micro-Controller 40kHz Chopper Frequency Divider / N 2.3 - 2.6 GHz PLL Oscillator ADF4113 + VCO 10 MHz TCXO 1ppm Pulse Width Modulator SG 2525 Divider / R 1.5 kW Power Supply Phase - Freq Detector & Charge Pump Loop Filter 325 V DC + 5% 100 Hz ripple ADF 4113
Way Forward • Commission the development of a 704MHz Magnetron (440kW) • Procure standard modulator • Set up test station with IOT as drive amplifier • Understand locking characteristics of new magnetron • Commission advanced modulator with in-pulse current control • Establish minimum locking power • Establish two magnetron test stand • Develop LLRF for simultaneous phase and amplitude control Demonstration of CW 2.45 GHz magnetron driving a specially manufactured superconducting cavity at JLab due later this month should stimulate more interest.
WG1 Presentations Tuner Design & Performance G. Devanz (CEA) Third SPL Collaboration Mee Development paths for High average RF Power Couplersing, CERN November 2009
Can be corrected with room temperature tuning using plastic deformation: • Fabrication tolerances • Main cavity treatments : • 800°C heat treatment against Q desease, • First heavy chemical treatment (150 to 200 mm) • Field inbalance between cells Tuning system requirements Has to be corrected with the cold tuner: • The remaining error of the room temperature tuning • The effect of the last chemical treatments • The differential shrinkage of materials of the cavity, He vessel and tuner • He Pressure, Lorentz detuning, However: • Last points (diff. Shrinkage) can be taken into account for series cavities after the full test of the first prototype RANGE? (also operation/commissioning of the accelerator) G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Slow tuner with symmetric action • Excentric/lever arm provenSaclay design • Planetary gear box (3 stages) • Single NOLIAC 30mm piezo actuator • Stiffness measured on the tuner pneumatic jack = 35 kN/mm • Initially developed for the beta=0.5 5-cell cavity Saclay piezo tuner for 700MHz cavities G. Devanz CEA-Saclay, SPL 3rd coll. meeting
4.5 K, amplitude = +760kHz corresponding to 2.5 mm -> would be +400 kHz on SPL beta=1 cavity • Mechanical hysteresis measurements will be done at 2 K Beta 0.5 cavity tuning butée mécanique G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Transfer function measurements G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Transfer function measurements ? Phase demodulation measurements at 1.8K in Cryholab TF piezo drive voltage -> cavity detuning can be used to identify the mecanical modes of the system, especially modes generating most detuning (220 Hz) Reproductible measurements except in the 100-160 Hz range (why?) Fcav=703 MHz, far from tuner neutral point G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Piezo detuning (DC) measured at 1.8 K (main tuner parts at 20 K) piezo 44V for 1 mm elongation of the cavity ( ~2 mm for the piezo actuator) Maximum detuning measured at 150V DC = +1 kHz G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Conclusion • Piezo tuner is working as expected • Caracterization of the cavity is going on • Lorentz Force Detuning compensation not yet tested, will be done with the fixed and modified HPVS, with long pulses 2ms, 50 Hz • Preliminary compensation tests with 2 ms, 5 Hz are foreseen in the upcoming weeks • The CERN crate is working now as an fast IQ acquisition system, will be used as the piezo controler, and ultimately a adaptive feed-forward for LFD compensation could be implemented. G. Devanz CEA-Saclay, SPL 3rd coll. meeting
Power Couplers - Presentations • Coupleurs XFEL - A. Falou (LAL) • Conditionnement Coupleurs TTF-3 - L. Lukovac (LAL) • CEA Coupler Tests – G. Devanz (CEA) • SPL Coupler Options Integration - E. Montesinos(CERN) • Development of High av. power Couplers - E. Montesinos(CERN) Third SPL Collaboration Mee Development paths for High average RF Power Couplersing, CERN November 2009
SPL 3rd Collaboration Meeting (CERN/ from 11 to 13 November 2009) IN2P3 Les deux infinis Aboud Falou (LAL-Orsay) XFEL Power Couplers 1.3GHzTechnical Specification & Industrial StrategyLAL contribution to XFEL linac at DESY sLHC
XFEL RF Couplers/ from R&D to Mass Production SOMMARY • Power Couplers main components & technical performance • Interfaces with cryomodule & string cavities • Industrial studies & coupler prototypes • RF contact evaluation • Market Strategy for mass production (Technical Specifications) • Manufacturing Sequence & Transport/Storage logistic • Time schedule 2009/2012
XFEL RF Couplers/ from R&D to Mass Production Functional Parts of XFEL Coupler (M.Lacroix) Warm Ceramic (TiN in) Pick-up e- Motor Capacitor Pumping Port Cold Ceramic (TiN in-out) Cold Bellows 298K RF Antenna Warm Bellows Cavité Supraconductrice Warm Transition 77K Warm Part 4K 1.8K Faisceau d’électrons Cold Part +/-10mm
XFEL RF Couplers/ from R&D to Mass Production Major non conformities (TTF-3 Inspections) • SS welding performance (full penetration, roughness & seam flatness at RF side). • Cupper/ceramic brazing (tensile resistance, tightness, metallic projections). • TiN & Cu surface coating (matrix adhesion, thickness control, roughness, boundary lines). • Final ‘welding’ assembly (alignment of in/out conductors, penetration, metallic projections). • Cleaning procedures, difficult access to residual particles. • Wave Guide Boxes soldering (lack or excess of metal, acid discoloration). • RF contact between Wave Guide Box & coupler flanges (misalignment, sparks). • Translation mechanism of RF antenna (alignment, mechanical constraints). • Bolting dysfunction under UHV environment (grippage).
XFEL RF Couplers/ from R&D to Mass Production Industrial Studies & Coupler Prototypes • . Brazing final assembly, 2 proto Feb 2008 from Toshiba • Cleaning non conformity, couplers complete dismounting at LAL, fully cleaning up, drying and remounting. • Automatic RF processing failed, many vacuum interlocks. RF manual processing was successful. • Possible failure reasons: High T°C TiN cycles, Hollow antenna. • . EB weld final assembly, 2 proto March 2008 from Accel • Cleaning non conformity, back to the company and fully cleaned up. • Automatic RF processing successful, few interlocks. • RF contact failed during sweeps (capacitor springs assembly).
XFEL RF Couplers/ from R&D to Mass Production Industrial Studies & Coupler Prototypes • . EB weld final assembly, 2 from Thales (Tin & Cr2O3) • Automatic RF processing successful, few interlocks. • RF contact identical to TTF-3 design. • . EB weld final assembly, many TTF-3 couplers from CPI • Automatic RF processing successful, few interlocks. • Engineering non conformance during visual inspections. • Couplers under operation at FLASH experiment.
XFEL RF Couplers/ from R&D to Mass Production Industrial Studies/ Accepted & rejected proposals {manufacturing techniques} Single Block Machining, Non optimized cost Forming by Deep drawing, recommended Pull out + circular weld Smooth RF surface Saddle weld, not recommended Final brazed assembly, not accepted to prevent TiN coating Final EB or TIG weld, recommended.
XFEL RF Couplers/ from R&D to Mass Production Industrial Studies/ Accepted & rejected proposals {Wave Guide Box} Boîtier guide d’ondes: la conception d’origine TTF-3 est un assemblage brasé de pièces cuivre, laiton et acier inoxydable. La membrane Cu donne la flexibilité pour le contact RF. Boîtier guide d’ondes: Usinage sur CN d’un bloc massif d’aluminium exempt de soudures et brasures. Variante possible pour la production de série si le contact RF ne nécessite pas de flexibilité.
XFEL RF Couplers/ from R&D to Mass Production Séquences de Fabrication Moteur pas à pas Spécification Matière et Approvisionnement Mise en forme, usinages, soudages, brazages Boîtier Guide d’onde Support des coupleurs sur cryo module Dégraissage, Nettoyage Mécanisme d’ajustement de l’antenne Fenêtres Céramique + TiN Soudage sous-ensembles Bride sur vide isolation Contrôle Qualité, Test He et mesures géométriques Partie chaude (77K-300K) Nettoyage final, étuvage comptage des particules Assemblage final parties chaude, froide et cavité Ecran Thermique 77K et 4K Partie froide (2K-77K) Emballage, transport LAL CP sous vide, WP sous N2
XFEL RF Couplers/ from R&D to Mass Production Planning 2009-2012 CCTP/CCAP début (Avril) Revue de projet IN2P3 (06/Juillet) 2009 CCTP/CCAP fin (Dec) CEC/PRR (Janvier) Appel d’offre (Fevrier) 2010 Notification marché Avril Préséries {2x12 unités} Fin Préséries 2011 Montée progressive Régime nominal 2x4 unités par semaine 2012
3rd SPL Collaboration Meeting (CERN, 12 November 2009) IN2P3 Les deux infinis Lucija Lukovac (LAL) RF Conditioning of TTF3 Input Power Couplers & Acceptance Criteria for XFEL
RF conditioning of TTF3 power couplers RF conditioning procedure Warm test stand : travelling wave mode @ LAL Procedure Test stand Control parameters Cryomodule - reconditioning : standing wave mode @ DESY Off resonance = Warm test stand On resonance 20 μs -> 200 μs Pmax = 1 MW 400 μs Pmax = 330 kW 500 μsflat top + flat top 100 μs, 200 μs, 400 μs, 800 μs Pmax = 250 kW sweeps 500 μs + flat top 800 μs
Acceptance criteria for XFEL power couplers Conditioning : Infrastructure clean room (cl. 10 000 / iso 7) mobile clean room (cl. 100 / iso 5) stock RF station Managed by E. Genesseau (LAL)
Acceptance criteria for XFEL power couplers Conditioning : lessons learned from TTF3 couplers Cleaning & Assembly • Class 10 clean room • US bath cleaning with detergent + high temperature • Drying with filtered N2 and under laminar flux • Particle count • Leak test Cleaning & assembly procedure @LAL To be performed by the manufacturer ! Follow the procedure M. Lacroix et al., LAL internal report
Acceptance criteria for XFEL power couplers Conditioning : lessons learned from TTF3 couplers In situ baking Gas analysis H. Jenhani et al., NIM A 595 (2008)
Acceptance criteria for XFEL power couplers Accepting a coupler : good or excellent? Example of refused coupler • Mechanical : dimensions, visual inspection • Material tests (TiN & Cu coatings) • Following the cleaning and assembly procedure • Particle count • Leak tests • In situ baking gas analysis • Time needed to achieve given power level • Total conditioning time => excellence • Number of interlocks => refusal
doorknob (air) 100 mm diameter 50 W 704 MHz -1 MW power couplerG. Devanz vacuum gauge electropolished water cooled inner conductor water cooled RF window cryostat flange He cooled outer conductor Designed for 1MW, 10%DC G. Devanz 3rd SPL Meeting Nov. 2009
Water circuit • KEK like design , disk window matched with chokes • water cooling of the antena and the internal braze of the ceramic Coupler - window internal conductor dissipation for 100kW average incident power G. Devanz 3rd SPL Meeting Nov. 2009
parts ultrasound cleaning, high purity water rinsing • assembly in clean room (couplers+coupling box) • couplers always handled in vertical position • clean room compatible handling tools • rail and cart system to move heavy parts • 200°C 48h in-situ baking of the vacuum parts Coupler & stand preparation G. Devanz 3rd SPL Meeting Nov. 2009
Assembly of the couplers in class 10 clean room G. Devanz 3rd SPL Meeting Nov. 2009
Couplers are conditioned in horizontal position RF power source : 1 MW klystron 2ms 50Hz Pulsed HV power supply : 110 kV 2.5 A HVPS and modulator Circulator commissioned with full reflected power, all phases Oil-free pumping (high pressure turbomolecular+scroll pump) 704 MHz coupler test stand Fully functional test stand TW setup with load SW setup with sliding short G. Devanz 3rd SPL Meeting Nov. 2009
Coupler conditioning • Maximum en TW 1.2 MW peak @10% DC • Total duration. 300h • SW conditioning stopped due to HVPS failure in march09, then had to proceed with the coupler installation on the test SC cavity • Repair of the 110kV 2.5A still going on, coming back end of november • Othe HVPS were available at the lab to operate with a lower duty cycle. G. Devanz 3rd SPL Meeting Nov. 2009